Micro Made Simple- Chapter 15. Bacteria Without Cell Walls

Front 1

What are the tiniest free-living organisms capable of self-replication on the planet?

Back 1

Mycoplasma. Smaller than some of the larger viruses.

Front 2

What is unique about mycoplasma?

Back 2

Lack a peptidoglycan cell wall. They only have a protective cell-membrane that's packed w/ sterols (ie. cholesterol) to help shield organelles from the outside worod.

Front 3

What is the consequence of lack of peptidoglycan cell wall for mycoplasma shape?

Back 3

Contortion into broad pleomorphic forms can occur (from round to oblong). Thus they are not classified as rods or cocci.

Front 4

How effective are penicillins, cephalosporins, erythromycin, and tetracycine antibiotics against mycoplasma?

Back 4

Lack of a cell wall makes antibiotics that target cell wall (penicillin/cephalosporin) inneffective.

However, anti-ribosomal antibiotics (erythromycin/tetracycline) are QUITE effective.

Front 5

2 pathogenic species of mycoplasmataceae

Back 5

1. Mycoplasma pneumoniae

2. Ureaplasma urealyticum

Front 6

The sterol-padded cell membrane of mycoplasma

Back 6

Penicillin and cephalosporin fail to tear down the cell membrane, but they can easily destroy gram-positive streptococcus.

Front 7

Mycoplasma pneumoniae causes what clnical disease?

Back 7

"Walking pneumonia" --a mild, self-limited bronchitis and pneumonia.

CXR: streaky infiltrate (looks worse than symptoms, PE suggest). This can also be seen and is consistent with a more viral picture.

Front 8

#1 cause of bacterial bronchitis and pneumonia in teenagers and young adults

Back 8

mycoplsama pneumo-->walking pneumoniae..

Called so because, well, patients don't really feel all that sick.

Front 9

Mycoplasma pneumoniae transmission and infectious course

Back 9

Organism is transmitted via respiratory route-->attachment to respiratory epithelium via P1 (adhesin virulence factor)

After 2-3 weeks incubation-->gradual onset fever, throat, malaise, persistent dry hacking cough.

In 1 week, these symptoms can resolve, but the cough and infiltrate (seen on xray) can last up to 2 mos.

Front 10

Sputum culture

Back 10

Mycoplasmataceae (m. pneumoniae/ u. urealyticum) must be grown on artificial media rich in cholesterol and contain purines/pyrimidines).

2-3 weeks later, a tiny dome-shaped colony of mycoplasma will assume a "fried-egg" appearance.

Front 11

Mycoplasma DNA probe

Back 11

Sputum samples mixed with labeled recombinant DNA sequence homologous to that of mycoplasma. The recombinant probe will label mycoplasma DNA if present.

Front 12

Tx. of walking pneumonia

Back 12

Self-limiting walking pneumonia caused by mycoplasma pneumoniae can be shortend by a dose of erythromycin and tetracycline (which target the bacterial ribosome)

Front 13

Ureaplasma urealyticum

Back 13

WHOAH THERE! Why wasn't this puppy named MYCOPLASMA? Obviously, the man who named this little guy didn't want you to forget that Ureaplasma urealyticum loves to swim in urine and produce urease to break down urea (so it's "urea-lytic"!) Often called "T-strain" mycoplsama, as it produces "T"iny colonies when cultured.

Present in 60% of active-sex-girls, it likes to hang out in urine places (like the lower urinary tract, causing urethritis).

Front 14

Bacteria that can cause urethritis

Back 14

Ureaplasma urealyticum, neisseria gonorrhoeae, and chlamydia trachomatis.

Front 15

Ureaplasma urealyticum identification

Back 15

Can be ID's by its ability to metabolize urea into ammonia and CO2.